Process for the production of light-sensitive materials for color photographic purposes



Patented Sept. 5, 1939 PATENT oFF ce PR CESS FOR PRODUCTION OF LIGHT- SENSITIVE MATERIALS FOR COLOR PHO- TOGRAPHIO PURPOSES vBela. Gaspar, Brussels-Forest, Belgium No Drawing. Application February 16, 1938, 802- {$17 No. 190,878. In Germany February 20,

9 Claims.

The present invention relates to a process of producing photographic materials for color photographic purposes which enables insoluble or diflicultly soluble dyestufi components to be incorporated in the photographic colloid in a very simple and reliable manner. The process consists in incorporating the desired dyestuif component in the colloid not in the form of the component itself but in the form of a soluble. de-

rivative thereof the component being subsequently split oif from its derivative dissolved within the colloid. By the term dyestufl component is meant any substance capable of forming a'dyestuff by reacting or coupling with a second dyestufi component, if necessary after a.

pretreatment such as, for instance, diazotizing.

The soluble derivative is preferably one that is derived from an organic dyestufi component hav-' ing an at least bi-valent inorganic atom linkedto 2a a carbon atom of the molecule and a radical imparting a salt-forming character hydrolysably linked with the said inorganic atom in which case the splitting oif of the component is effected by hydrolysis. More particularly, the bisulfite and aldehyde bisulfite addition products of a20- dyestufl components, the w-SlllDhOlliO acid salts of the amino compounds and the sulphaminic acid salts derived from tlitlyestufl forming substances containing an amino for carrying out this process. V The process of producing light-sensitive'materials according to the present invention, therefore, consists in" incd'rporating into the solutions: employed for the production of the emulsion, into the emulsion itself or into the finished lightsensitive layer, s'o'lubfe derivatives of insoluble or difilcultly soluble dye'stufi components, the 'said derivatives being split up to give the-dyestuif components to be employed in the production of the colored image prior to exposure of the, material; The present invention is generally applicable to dyestuil' components in the light-sensitive material whatever be the method subsequently employed for the production of they colored image.

Thus, for example, the processes covered bymy prior Patents Nos/2,071,688 and 2,046,067 require the'presence of dyestufi components in the lightsensitive layer, the dyestufl employed for the proto duction of the image being formed from these components after exposure. Other I processes which require the presence of dyestufi compon- 'ents in'thelight-sensitive layer have been described, for example, in British specifications 55 Nos. 298,979 (Lierg) and 15055/1912 '(Flscher),in

group a are suitable theincorporation of insoluble or diflicultly soluble both of which the advantage of using insoluble or diflicultly soluble dyestufl. components 'is stressed.

Heretofore, water-insoluble dyestufl components have been ,incorporatedinto the materials 5 as such, for example, by dissolving them in alcohol and mixing the alcoholic solution with the gelatine solution. Alternatively, salt forming dyestuif components-were used inthe form of water-soluble alkali-salts from which the dye- 10 stufi component was precipitated. The first ot these methods has the disadvantage that upon mixing the alcoholic solution with the gelatine an immediate precipitation of the dyestufl components takes place, this giving a much more un- 15 even precipitation than the process of the present invention, in which precipitation is only. brought about after the dyestufi component has become evenly distributed throughout the whole of the emulsion or the gelatine employedior the 20 production of the photographic colloid.

The precipitation of insoluble dyestufi components from th alkali-salts thereof is only possible with a limited group of dyestufl. com-.

ponents. On-the other hand, the soluble deriva- 25,

tives of the dyestufl components used in carrying out thepresent invention are substitution products which cannot be reconverted into the soluble deriyativeiafter they have once been'split up within the layer. Accordingly they may, if 30 necessary, be so chosen that they are not dissolved in the developer.

The splitting .up of the soluble derivative in carrying out the present invention Isis. comparatively slow reaction which extends throughout 35 the whole'of the emulsion and/or colloid and consequently the insoluble or difflcultly soluble component is produced in a state of very fine subdivision.

Within the expression insoluble or diflicultly 40 soluble dyestufi components used herein are included not only those dyestuff components which are practically insoluble in water or the emulsion 'but alsothose dyestuff components, the solubility of which is insufiicient to enable a sufliclent 45 quantity for practical use to be dissolved in the emulsion. If, for example, a dyestufl' component is soluble in water to the extent of one part in one hundred, then only one-half per cent of the component can be introduced into the emulsion by mixing equal quantities of the solution and the emulsion. The use of a larger amount 01' Water to increase the amount of dyestufr present results in a dilution of the emulsion which is,a,

disadvantage. I

As above stated, the light-sensitive materials according to the presentinvention contain the dyestuii' components, after splitting up, in an extremely finely divided state whereby they, despite their insolubility, readily react with the subsequently applied reagents to' produce an intense dyeing of the layer. The dyestuif may be produced diffusely throughout the layer or locally at the image or non-image parts thereof accordponents.

Benzidine is used in the form of the sodium salt of the benzidine-N-N'-dimethyl-w'-disulphonic acid (see Bucherer- 8r Schwalbe, Berichte de Deutschen Chemischn Gesellschaft, 1906 volume 39, page 2805). This derivative is incorporated in the gelatine which is to be used for preparingthe emulsion or which is to be added to the light- 5 sensitive emulsion, and the gelatine is then treated with a weak solution (say 1%) of ammonia, sodium carbonate or other alkali. The gelatine in allowed to stand at a temperature of about 40 C. in order that the splitting up may be completed. It is then coagulated, brought into noodleform, washed and after re-melting is mixed with the light-sensitive emulsion. I

In place of benzidine, other amines such as p-naphthylamine, tolidine or dianisidine may be used in the form of the N-methyl-u-sulphonic acid salts or the homologues obtained, for example, from acetaldehyde-bisulfite or benzaldehyde-bisulflte compounds.

The amines may also be used in the form of sulphaminic acid salts of which naphthylamine sulphaminic acid (Berichte volume 24 pages 360 and 363) may be cited as an example. Such a derivative is split up by means of diluted acid.

Phenol may be used in the form ofa phenylsulphonic acid salt such as CsHsO.SO:Na (Verley,

Bull. Soc. Chim. de France, part 3, vol. 25, pages 46-49). Naphthol may alsobe used in the form' of the naphthyl sulphonic acid salt and similarly a-dinaphthol in the form of the corresponding sulphonic acid ester.

For the incorporation of difiicultly soluble phenols, the esters that these phenols form with bi-valent organic acids may also be used. The salts of such esters have the formula, for example,

co-ox oo-oNs where ox indicates the phenolic residues and R a bi-valent organic radical. Such salts, of which thymol-suecinic acid is an example, have been described, inter alia, in German patent specifica Men No. 11129"! (Wellcome).

Dyestufl components of the aceto-acetic ester type may be used in the form of their bisulfite compounds. Thus, for example, the isoamyl ester of aceto-acetic acid is dimcultly soluble, whilst its bisulfite compounds, which are capable of being split up as herein described, are readily soluble.

aivaaos Such bisulfite compounds may be prepared in an analogous manner to the preparation of the bisulfite compound of the aceto-acetic ester described by Ellen, Recueil des Travaux Chimiques des Pays-Bas, volume 3, page 245. 5 Aldehydes may also be used as the dyestuif components. Thus for example, 3-nitrobenzaldehyde may be used in the form of its bisulfite compound. The aldehyde yields a red-yellow dyestuil' with 'di-hydrazine-stilbene-disulphonic [0 acid after the splitting up. Corresponding bisulfite compounds of naphthaldehyde are also known (see, for example, Berichte vol.2l page 259) and the same may be used in the like manner in carrying out the present invention. The 15 splitting up of the addition compounds is eflected by means of weak alkalis.

As a further example of the present invention may be cited the use of a dyestuif component which itself has a fairly high solubility in water go but which, in order to reduce the aqueous dilution, is'used in the form of a still more easily soluble derivative in order that it may be introduced in a higher concentration into the photographic colloid. For example, the di- 35 methyl-di-omega-sulphonic acid sodium saltof Diazo light yellow (Fierz-David 1926 page 154) is used instead of the Diazo light yellow itself. This salt is formed in a mannersimilar to that of the corresponding benzidine salt above referred to 30. and is split up in the emulsion prior to exposure. According to a further feature of the'present invention the splitting up of the soluble derivatives of the insoluble. or dimcultl'y soluble dyestufi components is carried out in the presence 35 of a precipitating agent that yields an insoluble and non-diffusing salt of the dyestufi' component set free on the splitting up. By this means the dyestufi. component will be fixed in an extremely finely divided state even when dyestui! corn 4a."

ponents which themselves are not completely insoluble are employed. Suitable precipitating agents are, for example, di-phenyl guanidine and. quaternary naphthoquinolinium salts.

invention, the splitting up of the soluble deriva-.- tives of the dyestufl components is effected in the presence of wetting agents and emulsifying agents. The use of such agents produces an especially fine dispersion of the dyestufi' com- 50' ponents. Suitable agents for use in carrying out this feature of the present invention are, for example, soap derived from sulphonated castoroil (known in Germany as Monopolselfe) fatty acid sulphinates, salts of cholic acid, lignon-sulphonic 6i The method of the introduction of the dyestufl 08' components will be described by way of anexample showing in what manner a component is incorporated into the light-sensitive emulsion' using its formaldehyde bisulfite compound. 5 g. of the formaldehyde bisulfite compound of to an amine is dissolved in 50 com. water at about C. 50 com. of a gelatine solution of 20% strength are added with stirring and also 5 com.

' 2-n hydrochloric acid. It is also possible to use alkali instead of the hydrochloric acid for split- 16' According to a further feature of the present a" ting up the formaldehyde bisulilte compound. The gelatine solution is stirred for hall an hour at about 50 C. In this case also about twice the quantity 01' sodium hydroxide may be used afterwards. The gelatine so produced contains the amine set free by the formaldehyde bisulilte compound. The gelatine is later mixedwith the photographic emulsion; 5 com. 01 the ordinary blue sensitive-unripened emulsion is used, {or example, and 1 com. of the amine-containing gelatine solution and 2 com. of water are also added.

The emulsion so prepared is then poured upon a glass plate or upon another support.-

The directions listed above can be used in the introduction 01' aniline, N-methyl-aniline, alphanaphthyl-amine, ortho-anisidine by means of the corresponding omega-suli'onic acid.

-Ii the introduction of phenols into gelatine is :concerned, the following procedure can be adopted for example. For the purpose of preparing its sulphuric acid ester the di-naphtol already named above is dissolved in pyridine and this solution is added to a solution-of chlorosulphonic acid in pyridine. For example, 11.2 g. dinaphtol and 8 ccm. chloro-sulphonic acid are used and the solution of the dinaphtol is slowly added to the solution of the chloro-sulphonic' acid; then the mixture is heated for 5 hours on the water bath; after this the pyridine'is distilled oil in vacuo and then the remainder is dissolved in an aqueous sodium acetate solution of 27.2% strength out of which the compound crystallizes in long needles on cooling. 0.1 g. oi!

3 the materialthus obtained is dissolved in 12 com.

oi. gelatine solution of 20% strength, the dinaphtol compound being added .in the iormof a solution in 2 ccm. of water and 1 com. oi 2-n hydrochloric acid. In warming to about 65 0. and in stirring during /z-hOUI' at this temperature the dinaphtol splits itself oil. While the sulphuric acid ester of the dinaphtolgis incapable of coupling itself'with diaho solu'glons, the gelatine on the other hand has the property of coupling with diazo-solutions after the treatment at an increased temperature in the presence of acid. The gelatine is mixed with a light sensitive emulsion poured on to a glass plate and is converted into dyer layers aftertheexposure and developing with diazo solutions; from these layers the dyestufi can be removed locally in the known manner for the production of dyestufl images.-

In a similar manner that compound which arises when 1 g. of the substance is dissolved in com. pyridin and heated with 3 g. of the halfchloride of the m-sulphonic benzoic acid for three hours and then pouring the mixture into water, and then salting out the soluble compound thus formed by means of the addition of sodium chloride, can also be used as a scisslble compound of the a di-naphtol. v

The invention does not limit itself to the use of the substances given as examples, but can also he used in order to introduce other dyestuif components, as for example diphenylamin, in the form of its, soluble scisslble compounds, for ex-- ample the formaldehyde bisulfite' compound, into the gelatine or the emulsion and from this to set free the component before the exposure.

In this case as in other cases the principle of the new process is based on the fact that an insoluble or difiicultly soluble dyestuijf component is incorporated into the layer in such a' way that one of its derivatives is produced which contains a radical which can be split oil againl-athis i'adie cal makes the component soluble; before the exposure, the soluble derivative is split up into the original component which then remains in .the

layer and is-used alter the exposure for the production of the dyestufl which is to form the image. In general the radical which can be split oi! consists of a salt-forming group which is linked to the dyestuiI component by a hydrolysable linkage. In most cases an inorganic atom forming a. part of the component such as for instance the oxygen atom 01' a phenolic component or a nitrogen atom of an amino or iminocompound brings about the union with the radical which can be split OH to form again the phenol or the amino compound.

What I claim is:

l. The'method of coloring a photographic materia with an azo-dye by incorporating into the colloid used for forming a layer of said material a Water insoluble azo-dye component having an inorganic atom, selected from the group consisting of oxygen and nitrogen linked to a carbon atom, and synthesizing the azo-dye within said colloid from said insoluble component, which comprises, the steps of dissolving a derivative of said insoluble azo-dye component in the colloid,

' having an inorganic atom selected from the group consisting of oxygen and nitrogen linked to a carbon atom, and synthesizing'the azo-dye' within saidgelatin layer from said insoluble component, which comprises the steps of dissolving a derivatlve of said insoluble azo-dye component in the gelatin solution, said derivative having an acid salt-forming radical in hydrolyzable linkage with said inorganic atom of the azo-dye component,

treating said derivative and the gelatin simultaneously and prior to pouring with a hydrolyzing agent which does not adversely affect said gelatin solution andwhich splits ofi s'aid insoluble dyestuif [component from the soluble derivative." 3. The method of coloring a photographic material with an azo-dye by incorporating into the gelatin solution used for forming a light sensitive silver halide gelatin layer of said material a waterinsoluble azo-dye component having an inorganic atom selected from the group consisting of oxygen and nitrogen linked to a carbon atom, and synthesizing the azo-dye within the layer from said insoluble component, which comprises the steps oi dissolving a derivative of said insoluble azodye component in the gelatin solution, said derivative having an acid salt-forming radical in hydrolyzable linkage with said inorganic atom of the azo-dye component, mixing the'gelatin solution with silver halide, treating said derivative and the silver halide colloid simultaneously and prior to the exposure of the photographic mate- 'rial with a hydrolyzing agent which does not adveisely ailect said silver halide colloid and which splits oil said insoluble dyestufi component from the soluble derivative.

4. The method of coloring a photographic material with an azo-dye by incorporating into the silverhalide emulsion used'ior forming a light sensitive silver halide emulsion layer oi saidmaterial a water insoluble azo-dye component having an inorganic atom, selected from the group consisting of oxygen and nitrogen linked'to a carbon atom, and synthesizing the azo-dye within the layer from said insoluble component, which comprises the steps of dissolving a derivative. of said insoluble azo-dye component in the silver halide emulsion, said derivative having an acid salt-forming radical in hydrolyzable linkage with said inorganic atom of the azo-dye component,

treating said derivative and said silver halide emulsion simultaneously and prior to the exposure of the photographic material with a hydrolyzing agent which does not adversely affect said silver halide emulsion and which splits oiI said insoluble dyestuilf component from the soluble derivative.

5. In a process oi producing photographic materials which includes incorporating a soluble hydrolyzable derivative oi an insoluble azo-dye component into a colloid used for the formation of a layer of said photographic material, said azo-dye component havingan inorganic atom selected from the group consisting of oxygen and nitrogen linked to a carbon atom of the molecule and said derivative having an acid salt-forming radical linked in hydroiyzable linkage to said inorganic atom, the step which consists in treating said colloid and said derivative, simultaneously and prior to exposure by a hydrolyzing agent which does not adversely afiect said colloid.

6. In a process of producing photographic materials which includes incorporating a soluble irvdrolyzable derivative of an insolubleazo-dye component into a colloid used for the formation of a-layer oi said photographic material, said azo-dye component having an inorganic atom selected from the group consisting of oxygen and nitrogen linked to a carbon atom of the molecule and said derivative havingan acid salt-forming radical linked in hydrolyzable linkage to said inorganic atom, the step which consists in treating said coloid and said derivative, simultaneously and prior to exposure and in the presence oi a wetting agent by a hydrolyzing' agent which does not adversely aflect said colloid.

7. The method of producing photographic dyestuil images which comprises dissolving a derivative of an insoluble azo dyestui! component within the gelatin solution to be used for the production of a light sensitive silver halide emulsion layer on the support of the photographic material, said azo dye component having an in- 2,172,sos'

organic atom selected from the group consisting of oxygen and nitrogen linked to a carbon atom of the molecule and said derivative of the component having anacid salt-forming radical in hydrolyzabie linkage with said inorganic atom, splitting off the dyestufl component from the dissolved derivative within the gelatin solution by a hydrolyzing agent which does not adversely affect said gelatine solution, mixing the gelatin with silver halide, pouring said emulsion onto the support, exposing the light sensitive layer, developing the silver image, transforming the dyestufi component into an azo dyestui! and destroying the azo dyestuii locally-in proportion to the silver deposit.

8. The method of producing photographic eyestufi' images which comprises dissolving -;a derivative of an insoluble azo dyestui! component within the gelatin'solution to be used for. the production of a light sensitive silver halide emul-'- sion layer on the support of the photographic material, said azo-dye component having an in-' organic atom selected from the group consisting 'of oxygen and nitrogen linked to a carbon atom of the molecule and said derivative of the component having an acid salt-forming radical in hydrolyzable linkage with said inorganic atom,

mixing the gelatin with a silver halide, splitting off the dyestufl component from'the dissolved derivative within the silver halide-emulsion by a hydrolyzing agent which does not adversely aiiect said silver halide emulsion, pouring the said emulsion onto the support, exposing the light sensitive layer, developing the silver image and transforming the component into an azo dyeacid salt-forming radical in hydrolyzable link-' age with said inorganic atom, splitting oil the .dyestuil' component from the dissolved derivative within the gelatin solution by a hydrolyzing agent'which does not adversely afl'ect the gelatin solution, mixing the gelatin with silver halide, pouring the said emulsion onto the support, ex-

posing the light sensitive layer, developing the silver image and transforming the component into a dyestufl image.

' BELA GAsPAR. 

